Just to add onto the other answers, a slight mutation rate is actually built into us. It’s *possible* to make proteins (DNA polymerases) that are more accurate at replicating our DNA, but we don’t actually have them because some amount of diversity is good.
For a real-life example, the influenza virus has a relatively inaccurate polymerase, which causes lots more mutations, which is why it’s hard to make a perfect flu vaccine.
No one is 100% identical to their parents. Not even single celled organisms that basically split in half and clone themselves.
Each time a cell divides there are slight changes due to errors and that will accumulate over many generations. Some mutations will have huge effects but most will have slight.
Latest Answers